Electric motor replacement question

[Bob Vavricka]

521519521520 Given the breadth of knowledge in this forum, I have an electric motor question. The second picture is the nameplate for a bad motor from an air compressor. Would the motor in the first picture be a suitable replacement? The specifications look pretty close to me, but I'm not very knowledgeable in this area. Thanks.

[Jimmy Harris]

It seems like it's pretty much the same motor. The difference between them, that I can see, is the second one mounts via a bracket set below the motor, and the first mounts via bolt holes in the face. So you might be able to make it work, but it would take some fabrication to do so.

You can find exact fit replacements online if you haven't already purchased the first motor. If you have or can get it dirt cheap so it's worth it to you to try to make it work, it might be worth disassembling the motor and having a mounting bracket welded to the housing. Or figuring out some other way to mount it securely. You'll just want to take it apart as the welding process might create enough heat to damage the internals if you don't.

[Bob Vavricka]

The first one has both a base bracket and the c face mounting holes so I don’t think that will be an issue. Thanks.

[Bill Dufour]

The first motor is TEFC so it will not get clogged with dust, better in a shop. That will also make it a bit bigger and heavier. Not a problem for most uses. You know the bearing sizes so consider replacing them before using it if they feel the least bit worn or dry. A company that tells you bearing sizes on the data plate is a likely a good motor company. Baldor is top notch.
BilLD

[Richard Coers]

There are compressor duty cycle motors for commercial shop compressors that pretty much run for 8 hours. Just keep that in mind.

[Jimmy Harris]

I'm definitely not a motor expert, but the other thing I see is the first one is a Code J, and the second is a Code G (I think, it's hard to see). And from what I understand, that would mean the first one would likely need a larger starting capacitor and might need other components upstream beefed up. And lastly, the first one has a Service Factor one 1.00 vs. 1.15 on the second. This means the first one likely won't last as long under stress. I don't know how much an air compressor would stress the motor.

All in all, I would probably look for an exact replacement since those can be found and typically run a similar price. However, if you found a good deal on that one or already have it, and it has the capacitors already installed, then it might be worth a shot. I'm not seeing anything that says it won't work, just some stuff that says it might not work as well.

[Bill Dufour]

Air compressor. duty is one of the hardest for motors. Normal motors can withstand 10-12 starts per hour. More than that and the start windings over heat and insulation will fail soon. Not to be confused with the sears lying compressor horsepower motor. The motor makers took off the hP numbers and let sears make up numbers.
This is one reason why I recommended reduce pump RPm and pressure so the motor will not restart so often.
Bill D